Geological and geomorphological evolution of Luxembourg and its cuesta landscape

Abstract

Two different regions in Luxembourg are characterized by different substrates and landscapes. In the north, the plateaus with deeply incised valleys of the Eislek have developed in folded Devonian rocks. These rocks constitute the geological basement of the country. In the southern Gutland region, the Devonian basement is covered by a succession of Mesozoic sedimentary formations, gently dipping to the southwest. This succession of sedimentary rocks is expressed by an alternation of hard and soft rocks, which is responsible for the characteristic geomorphology of the cuesta landscape of the Gutland. The hard relief-building rocks are pervious, while the soft rocks of impervious nature form gentle slopes. The latter are of clayey and marly constitution and are sensible to variation in water content. Differential uplift and climatic changes have influenced the landscape development and fluvial incision processes since the Tertiary. The epigenetically developed drainage network has sculptured the present landscape. Generally, slope evolution is largely controlled by soil erosion and mass movements, rock fall in hard rocks and landslides in soft rocks. The intensity of landscape forming processes depends on the local climatic and hydrogeological conditions. Nowadays man's influence is not negligible any more, as expressed by the displacement of soil and rocks, as well as in triggering mass movements and agricultural induced soil erosion. This chapter introduces the general geological evolution of Luxembourg and surroundings, as well as the various geomorphological processes acting during the Tertiary and Quaternary. This will be illustrated by examples from the present landscape, which is the result of the interplay between geology, geomorphology, climate and the relatively recent influence by man.